Total hip replacement surgery is commonly performed to alleviate pain and loss of function in injured and diseased hip joints. During this surgery, the articulating surfaces of the hip joint are replaced with prosthetic bearing components. The replacement components generally include a femoral component having a convex bearing surface and an acetabular cup component having a mating concave bearing surface.
Modular femoral and acetabular components have become popular because they allow the surgeon to assemble components in a variety of configurations at the time of surgery to meet specific patient needs relative to size and geometry. For example, modular femoral components generally include separate stem and head components that can be assembled in a variety of configurations of surface finish, stem diameter, stem length, proximal stem geometry, head diameter, and neck length. Likewise, modular acetabular components generally include separate shell and liner components that can be assembled in a variety of configurations of surface finish, shell outer diameter, liner inner diameter, and constraining fit with the femoral head. With a modular acetabular component, it is desirable to lock the shell and liner tightly together to minimize debris producing wear between them. It is also desirable to maintain a predetermined minimum liner thickness to prevent penetration of the liner by the femoral component.